In systemic lupus erythematosus (SLE), the utility of serial anti-dsDNA antibody and complement measurements in clinical decision-making remains controversial. This study proposes two specific aims to address these issues. In specific aim 1, the investigators will collaborate with a large, multicenter NIH-sponsored protocol, the Safety of Estrogens in Systemic Lupus Erythematosus (SELENA) SPID #915, and perform an observational study to assess the sensitivity, specificity and predictive value of anti-dsDNA antibodies, C3, C4, CH50, C3a. Subgroup analyses will be performed in diverse ethnic groups of patients treated with exogenous estrogen who have chronically depressed CH50. In specific aim 2, an interventional study, the investigators will evaluate the effectiveness of short-term corticosteroid treatment in averting flares when elevations of palsma C3a are accompanied by rising anti-dsDNA antibodies.